RFR: 8027230: Overflow in java.lang.instrument.Instrumentation.getObjectSize() method

[Peter Allwin]

Hello!

Please review this simple fix for an integer overflow in JVMTI GetObjectSize().

webrev: http://cr.openjdk.java.net/~allwin/8027230/webrev.00/
cr: https://bugs.openjdk.java.net/browse/JDK-8027230


Testing:
	New regression test
	nsk.quick-jvmti.testlist

Thanks!
/peter